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(No Model.) Sheets-Sheet 1. P. J. SPRAGUB.

ELECTRIC RAILWAY SYSTEM.

Patented Oct. 20, 1885.

N PETERS, Pvwmuh (No Model.) 2 Sheets-Sheet 2. F. J. SPRAGUE.

ELECTRIC RAILWAY SYSTEM. No. 328,821. Patented 001;. 20, 1885.

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FRANK J. SPRAGUE, on NEW YORK, N. Y.

ELECTRIC-RAILWAY SYSTEM.

SPECIFICATION forming part of Letters Patent No. 328,821, dated October 20,1885.

Application filed August 27, 1885. Serial No. 175.422. (No model) To all whom it may concern.-

Be it known that I, FRANK J. SPRAGUE, of New York, in the county and State of New York,have invented a certain new and useful Improvement in Electric-Railway Systems, of which the following is a specification.

In my application filed February 27, 1885, of which this application isa division.,is shown and described, but not claimed, an electricrailway system in which two tracks are employed, each having a set of working-conductors, both said sets having a common source of electrical supply, preferably a main circuit extending along the line and connected at intervals to the working-conductors, each set of working-conductors having electric motors connected with them, the motors of each set being in parallel circuit with each other, and the motors of one set in parallel circuit with those of the other set. Additional cross-connections were also employed joining workingconductors of like polarity of the two sets.

The present application relates to such a system, and the same is illustrated partly in diagram in the accompanying drawings.

Figure 1 represents the preferred form of the invention, and Fig. 2 a modification thereof.

Referring to Fig. 1, A and A are dynamoclectric machines, situated at suitable stations at various points along the line, or for a short line only one station may be necessary. Each station has one or more such generators connected together, if there are more than one, in such a manner as may be desired, and having suitable means for regulating the supply of current, these being preferably adjustable resistances a a in the fieldcircuits of the machines.

P N are the positive and negative main conductors extending along the line. These conductors are preferably placed in a tube laid under ground, but they may, if desired, be supported overhead or by the side of the tracks, or arranged in any other convenient and suitable manner.

The railway has two tracks, B B and (J 0. Each track has a central or intermediate rail, D or E,which may or may not be divided into sections by interposed short sections of insulation. The rails 13 B D form aset of working conductors for one track, and the rails C O E form a set for the other track, the motors on each track being connected between the intermediate rail and the main or traffic rails thereof. It is evident,however, that the working-conductors,or those with which the motor makes contact to receive current, may be arranged in a great variety of ways. They may both be placed overhead or by the side of the track, or one may be overhead while the other may be the main rails or an intermediate rail,

.or the main rails may be insulated from the ground and each form one working-conductor, or the working-conductors may be constructed and disposed in any other manner in which the motor can conveniently make contact with them. In any case each track is provided with a set or pair of working-conductors. When the main rails are used and are not insulated from the ground, the earth of course forms part of this working-conductor.

The generators at the supplying-stations are connected with the main conductors. P N by supply-conductors b b, and the main conductors are connected with the working-coir ductors at intervals by branch conductors c c on one side and d d on the other side.

On track B B are motors F F, and on the other track are motors G G. Each of these is a wheeled vehicle which carries an electrodynamic motor, and motion is communicated from the armature of the motor to the driving-axle of the vehicle in any suitable manner. Each motor has contact-wheels e e, or springs or brushes may be used instead,which travel on the intermediate rail and are connected with one terminal of the motor, while the other terminal is connected with the wheels of the vehicle,which of course make contact with the rails which form the other workingconductor of the track. Each motor is pro,- vided with suitable means for regulating its speed and power and for reversing the direction of rotation of its armature. Adjustable resistances 1" in the armature-circuits, and r in the field-circuits, and circuit-reversers s, are shown for this purpose,- but any'of the motor-regulating means set forth in my prior patents may be used instead.

The circuits are from the generators by supply-conductors I) to main conductor P, by branch conductors 0 and d to interme IOC diate rails, D and E, through the motors to rails G O and B B, by branch conductors c and d to main conductor N, and by supplyconductors b back to the generators.

It will be seen that all the motors on each track are in multiple are or parallel circuit to each other or one another, and the motors on one track are in parallel circuit to those on the other track.

I may employ additional cross-connections h h, which connect working-conductors of like polarity of the two tracks, whereby the electro-motive force is equalized throughout the system.

It is evident that in some cases, as in short lines, the main conductors P N may be dispensed with and the supply-conductors from the one or more gcneratingstations connected directly with the working-conductors of the two tracks, in which case it is preferable to use the cross-connections already referred to. I prefer,however,to employ the main conductors in order to increase the currentcarrying capacity of the system, to provide a path for the current if any accident occurs to the working-conductors, and to admit of the division of the working-conductors into separately-supplied sections, when it is desired to do this. The modification referred to is, however, illustrated in Fig. 2. Here the terminals of generator A are connected by the supply-conductors directly with the rails 13 B and the intermediate working-conductor, D, of one track, and with the railsO O and working conductor E of the other track, the two sets of working conductors being thus connected in multiple arc with their common source of supply. Cross-connections h h are employed, as above described.

The supplying of the two tracks from one common source provides an efficient and economical system, and is especially advantageous in permitting the use of the method of braking set forth in my Patent No. 318,668, dated May 26, 1885, in which a motor is converted into a generator when the train is to be braked, and thus assists in supplying current to other motors which may be running on upgrades on either track. The cross-connections between the two sets of working-conductors are advantageous also for this purpose.

What I claim is 1. In an electric-railway system having two tracks, the combination of two sets of working-conductors, one set for each track, a common source of supply for said sets, and two or more motors connected with each set in parallel circuit with each other, substantially as set forth.

2. In an electric-railway system having two tracks, the combination of a source of supply with two sets of working-conductors, one set for each track, connected with said source and having motors connected with them, the motors of one set being in parallel circuit with those of the other set, substantially as set forth.

3. In an electric-railway system, the combination of a source of supply, two sets of work.- ing-conductors, and cross-connections at intervals between the sets joining conductors of like polarity, substantially as set forth.

4. In an electric-railway system, the combi nation of two sets of working-conductors, and a main circuit extending along the line and connected at intervals with both said, sets of working-conductors, substantially as set forth.

5. In an electric-railway system, the combination of two sets of working-conductors, a main circuit extending along the line, and branch conductors connecting the main conductors at intervals with both sets of i working-conductors, substantially as set forth.

This specification signed and witnessed this 22d day of August, 1885.

FRANK J. SPRAGUE.

WVitnesses:

H. WV. SEELY, JOHN W. HOWELL. 

